1. Field of the Invention
The present invention relates to an induction device, particularly to a high-efficiency induction device.
2. Description of the Prior Art
It is well known that an inductor may be applied to form a low-pass filter, and that the efficiency of the low-pass filter may be further improved by means of increasing the insertion loss resulting from the application of an additional capacitor.
In traditional technology, the combination of inductors and capacitors are realized by serially connecting one terminal of a substantial capacitor, i.e. a ceramic capacitor, to two inductors, thereby forming a three-terminal low-pass filter. As shown in FIG. 1(a), a traditional low-pass filter is comprised of a ceramic capacitor 10, two inductors 20, and three terminals 31, 32, 33. The two inductors are connected to one terminal of the ceramic capacitor 10, thereby forming the equivalent circuit shown in FIG. 1(b). This structure has the disadvantage of high cost and large volume and may not be fabricated to be a surface-mounted type (SMT) device.
Therefore, a SMT low-pass filter with low production cost is required in the industry.